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Merge remote-tracking branch 'public/pr/2925' into baremetal

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This commit is contained in:
Simon Butcher 2019-12-13 14:51:29 +00:00
commit e76c638d6f
16 changed files with 467 additions and 406 deletions
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143
tinycrypt/ecc_dsa.c
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@ -75,10 +75,10 @@ static uECC_RNG_Function g_rng_function = 0;
#endif
static void bits2int(uECC_word_t *native, const uint8_t *bits,
unsigned bits_size, uECC_Curve curve)
unsigned bits_size)
{
unsigned num_n_bytes = BITS_TO_BYTES(curve->num_n_bits);
unsigned num_n_words = BITS_TO_WORDS(curve->num_n_bits);
unsigned num_n_bytes = BITS_TO_BYTES(NUM_ECC_BITS);
unsigned num_n_words = BITS_TO_WORDS(NUM_ECC_BITS);
int shift;
uECC_word_t carry;
uECC_word_t *ptr;
@ -89,10 +89,10 @@ static void bits2int(uECC_word_t *native, const uint8_t *bits,
uECC_vli_clear(native);
uECC_vli_bytesToNative(native, bits, bits_size);
if (bits_size * 8 <= (unsigned)curve->num_n_bits) {
if (bits_size * 8 <= (unsigned)NUM_ECC_BITS) {
return;
}
shift = bits_size * 8 - curve->num_n_bits;
shift = bits_size * 8 - NUM_ECC_BITS;
carry = 0;
ptr = native + num_n_words;
while (ptr-- > native) {
@ -102,32 +102,31 @@ static void bits2int(uECC_word_t *native, const uint8_t *bits,
}
/* Reduce mod curve_n */
if (uECC_vli_cmp_unsafe(curve->n, native) != 1) {
uECC_vli_sub(native, native, curve->n);
if (uECC_vli_cmp_unsafe(curve_n, native) != 1) {
uECC_vli_sub(native, native, curve_n);
}
}
int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash,
unsigned hash_size, uECC_word_t *k, uint8_t *signature,
uECC_Curve curve)
unsigned hash_size, uECC_word_t *k, uint8_t *signature)
{
uECC_word_t tmp[NUM_ECC_WORDS];
uECC_word_t s[NUM_ECC_WORDS];
uECC_word_t p[NUM_ECC_WORDS * 2];
wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
wordcount_t num_n_words = BITS_TO_WORDS(NUM_ECC_BITS);
int r;
/* Make sure 0 < k < curve_n */
if (uECC_vli_isZero(k) ||
uECC_vli_cmp(curve->n, k) != 1) {
return 0;
uECC_vli_cmp(curve_n, k) != 1) {
return UECC_FAILURE;
}
r = EccPoint_mult_safer(p, curve->G, k, curve);
if (r == 0 || uECC_vli_isZero(p)) {
return 0;
r = EccPoint_mult_safer(p, curve_G, k);
if (r != UECC_SUCCESS) {
return r;
}
/* If an RNG function was specified, get a random number
@ -136,60 +135,66 @@ int uECC_sign_with_k(const uint8_t *private_key, const uint8_t *message_hash,
uECC_vli_clear(tmp);
tmp[0] = 1;
}
else if (!uECC_generate_random_int(tmp, curve->n, num_n_words)) {
return 0;
else if (!uECC_generate_random_int(tmp, curve_n, num_n_words)) {
return UECC_FAILURE;
}
/* Prevent side channel analysis of uECC_vli_modInv() to determine
bits of k / the private key by premultiplying by a random number */
uECC_vli_modMult(k, k, tmp, curve->n); /* k' = rand * k */
uECC_vli_modInv(k, k, curve->n); /* k = 1 / k' */
uECC_vli_modMult(k, k, tmp, curve->n); /* k = 1 / k */
uECC_vli_modMult(k, k, tmp, curve_n); /* k' = rand * k */
uECC_vli_modInv(k, k, curve_n); /* k = 1 / k' */
uECC_vli_modMult(k, k, tmp, curve_n); /* k = 1 / k */
uECC_vli_nativeToBytes(signature, curve->num_bytes, p); /* store r */
uECC_vli_nativeToBytes(signature, NUM_ECC_BYTES, p); /* store r */
/* tmp = d: */
uECC_vli_bytesToNative(tmp, private_key, BITS_TO_BYTES(curve->num_n_bits));
uECC_vli_bytesToNative(tmp, private_key, BITS_TO_BYTES(NUM_ECC_BITS));
s[num_n_words - 1] = 0;
uECC_vli_set(s, p);
uECC_vli_modMult(s, tmp, s, curve->n); /* s = r*d */
uECC_vli_modMult(s, tmp, s, curve_n); /* s = r*d */
bits2int(tmp, message_hash, hash_size, curve);
uECC_vli_modAdd(s, tmp, s, curve->n); /* s = e + r*d */
uECC_vli_modMult(s, s, k, curve->n); /* s = (e + r*d) / k */
if (uECC_vli_numBits(s) > (bitcount_t)curve->num_bytes * 8) {
return 0;
bits2int(tmp, message_hash, hash_size);
uECC_vli_modAdd(s, tmp, s, curve_n); /* s = e + r*d */
uECC_vli_modMult(s, s, k, curve_n); /* s = (e + r*d) / k */
if (uECC_vli_numBits(s) > (bitcount_t)NUM_ECC_BYTES * 8) {
return UECC_FAILURE;
}
uECC_vli_nativeToBytes(signature + curve->num_bytes, curve->num_bytes, s);
return 1;
uECC_vli_nativeToBytes(signature + NUM_ECC_BYTES, NUM_ECC_BYTES, s);
return UECC_SUCCESS;
}
int uECC_sign(const uint8_t *private_key, const uint8_t *message_hash,
unsigned hash_size, uint8_t *signature, uECC_Curve curve)
unsigned hash_size, uint8_t *signature)
{
uECC_word_t _random[2*NUM_ECC_WORDS];
uECC_word_t k[NUM_ECC_WORDS];
uECC_word_t tries;
int r;
uECC_word_t _random[2*NUM_ECC_WORDS];
uECC_word_t k[NUM_ECC_WORDS];
uECC_word_t tries;
for (tries = 0; tries < uECC_RNG_MAX_TRIES; ++tries) {
/* Generating _random uniformly at random: */
uECC_RNG_Function rng_function = uECC_get_rng();
if (!rng_function ||
!rng_function((uint8_t *)_random, 2*NUM_ECC_WORDS*uECC_WORD_SIZE)) {
return 0;
return UECC_FAILURE;
}
// computing k as modular reduction of _random (see FIPS 186.4 B.5.1):
uECC_vli_mmod(k, _random, curve->n);
uECC_vli_mmod(k, _random, curve_n);
if (uECC_sign_with_k(private_key, message_hash, hash_size, k, signature,
curve)) {
return 1;
r = uECC_sign_with_k(private_key, message_hash, hash_size, k, signature);
/* don't keep trying if a fault was detected */
if (r == UECC_FAULT_DETECTED) {
return r;
}
if (r == UECC_SUCCESS) {
return UECC_SUCCESS;
}
/* else keep trying */
}
return 0;
return UECC_FAILURE;
}
static bitcount_t smax(bitcount_t a, bitcount_t b)
@ -198,8 +203,7 @@ static bitcount_t smax(bitcount_t a, bitcount_t b)
}
int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
unsigned hash_size, const uint8_t *signature,
uECC_Curve curve)
unsigned hash_size, const uint8_t *signature)
{
uECC_word_t u1[NUM_ECC_WORDS], u2[NUM_ECC_WORDS];
@ -218,21 +222,18 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
uECC_word_t _public[NUM_ECC_WORDS * 2];
uECC_word_t r[NUM_ECC_WORDS], s[NUM_ECC_WORDS];
wordcount_t num_words = curve->num_words;
wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);
if (curve != uECC_secp256r1())
return 0;
wordcount_t num_words = NUM_ECC_WORDS;
wordcount_t num_n_words = BITS_TO_WORDS(NUM_ECC_BITS);
rx[num_n_words - 1] = 0;
r[num_n_words - 1] = 0;
s[num_n_words - 1] = 0;
uECC_vli_bytesToNative(_public, public_key, curve->num_bytes);
uECC_vli_bytesToNative(_public + num_words, public_key + curve->num_bytes,
curve->num_bytes);
uECC_vli_bytesToNative(r, signature, curve->num_bytes);
uECC_vli_bytesToNative(s, signature + curve->num_bytes, curve->num_bytes);
uECC_vli_bytesToNative(_public, public_key, NUM_ECC_BYTES);
uECC_vli_bytesToNative(_public + num_words, public_key + NUM_ECC_BYTES,
NUM_ECC_BYTES);
uECC_vli_bytesToNative(r, signature, NUM_ECC_BYTES);
uECC_vli_bytesToNative(s, signature + NUM_ECC_BYTES, NUM_ECC_BYTES);
/* r, s must not be 0. */
if (uECC_vli_isZero(r) || uECC_vli_isZero(s)) {
@ -240,31 +241,31 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
}
/* r, s must be < n. */
if (uECC_vli_cmp_unsafe(curve->n, r) != 1 ||
uECC_vli_cmp_unsafe(curve->n, s) != 1) {
if (uECC_vli_cmp_unsafe(curve_n, r) != 1 ||
uECC_vli_cmp_unsafe(curve_n, s) != 1) {
return UECC_FAILURE;
}
/* Calculate u1 and u2. */
uECC_vli_modInv(z, s, curve->n); /* z = 1/s */
uECC_vli_modInv(z, s, curve_n); /* z = 1/s */
u1[num_n_words - 1] = 0;
bits2int(u1, message_hash, hash_size, curve);
uECC_vli_modMult(u1, u1, z, curve->n); /* u1 = e/s */
uECC_vli_modMult(u2, r, z, curve->n); /* u2 = r/s */
bits2int(u1, message_hash, hash_size);
uECC_vli_modMult(u1, u1, z, curve_n); /* u1 = e/s */
uECC_vli_modMult(u2, r, z, curve_n); /* u2 = r/s */
/* Calculate sum = G + Q. */
uECC_vli_set(sum, _public);
uECC_vli_set(sum + num_words, _public + num_words);
uECC_vli_set(tx, curve->G);
uECC_vli_set(ty, curve->G + num_words);
uECC_vli_modSub(z, sum, tx, curve->p); /* z = x2 - x1 */
XYcZ_add(tx, ty, sum, sum + num_words, curve);
uECC_vli_modInv(z, z, curve->p); /* z = 1/z */
uECC_vli_set(tx, curve_G);
uECC_vli_set(ty, curve_G + num_words);
uECC_vli_modSub(z, sum, tx, curve_p); /* z = x2 - x1 */
XYcZ_add(tx, ty, sum, sum + num_words);
uECC_vli_modInv(z, z, curve_p); /* z = 1/z */
apply_z(sum, sum + num_words, z);
/* Use Shamir's trick to calculate u1*G + u2*Q */
points[0] = 0;
points[1] = curve->G;
points[1] = curve_G;
points[2] = _public;
points[3] = sum;
num_bits = smax(uECC_vli_numBits(u1),
@ -279,7 +280,7 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
for (i = num_bits - 2; i >= 0; --i) {
uECC_word_t index;
curve->double_jacobian(rx, ry, z, curve);
double_jacobian_default(rx, ry, z);
index = (!!uECC_vli_testBit(u1, i)) | ((!!uECC_vli_testBit(u2, i)) << 1);
point = points[index];
@ -287,18 +288,18 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
uECC_vli_set(tx, point);
uECC_vli_set(ty, point + num_words);
apply_z(tx, ty, z);
uECC_vli_modSub(tz, rx, tx, curve->p); /* Z = x2 - x1 */
XYcZ_add(tx, ty, rx, ry, curve);
uECC_vli_modSub(tz, rx, tx, curve_p); /* Z = x2 - x1 */
XYcZ_add(tx, ty, rx, ry);
uECC_vli_modMult_fast(z, z, tz);
}
}
uECC_vli_modInv(z, z, curve->p); /* Z = 1/Z */
uECC_vli_modInv(z, z, curve_p); /* Z = 1/Z */
apply_z(rx, ry, z);
/* v = x1 (mod n) */
if (uECC_vli_cmp_unsafe(curve->n, rx) != 1) {
uECC_vli_sub(rx, rx, curve->n);
if (uECC_vli_cmp_unsafe(curve_n, rx) != 1) {
uECC_vli_sub(rx, rx, curve_n);
}
/* Accept only if v == r. */
@ -309,7 +310,7 @@ int uECC_verify(const uint8_t *public_key, const uint8_t *message_hash,
return UECC_SUCCESS;
}
else {
return UECC_ATTACK_DETECTED;
return UECC_FAULT_DETECTED;
}
}